Daniel, who lost his sister, Zina, to domestic gun violence in a Brookfield, Wis., shooting in 2012, was joined by four other witnesses in the Senate Judiciary Committee's first-ever hearing on guns and domestic violence.

"Zina loved life. All she wanted to be was to be a good mother for her two daughters,'' said Daniel, as he tried to keep his emotions in check. "It has been nearly two years since Zina was murdered, and it is heartbreaking to know that our weak gun laws continue to allow dangerous abusers to buy guns without background checks.''

Zina Daniel's estranged husband, Radcliffe Haughton, had been served a permanent restraining order, which effectively prevented him from purchasing firearms. But gun-law loopholes allowed Daniel's husband to purchase a handgun through Armslist.com, an online site where private sellers are not required to perform background checks.

"To this day, I am convinced that the shooter deliberately bought the gun from an unlicensed seller because he knew he couldn't pass a background check -- and that if he hadn't been able to buy this gun, Zina would still be alive,'' Daniel said.

Roughly 40 percent of guns are processed without a background check, according to the Brady Campaign to Prevent Gun Violence.

Sen. Richard Blumenthal, D-Conn., and Sen. Amy Klobuchar, D-Minn., both have introduced bills in the Senate that would strengthen federal laws to keep guns away from domestic abusers.

Klobuchar's bill, the Protecting Domestic Violence and Stalking Victims Act of 2013, would expand a ban on possession and purchase of guns to abusive dating partners, convicted stalkers, and any form of intimate partner; while Blumenthal's bill would offer incentives and provide resources to states, encouraging them to take guns out of the hands of "dangerous people.''

"In most states, somebody subject to a temporary restraining order can lose access to his house, to his children and to his car, but under federal law he can still keep his guns,'' said Blumenthal. "Somebody might be considered too dangerous to see their son but not too dangerous to buy a handgun.''

Under federal law, abusers under a permanent restraining order are barred from purchasing guns, while those under a temporary order are not.

An estimated 48 women are shot to death by their intimate partner every month, according to Everytown for Gun Safety.

Sen. Sheldon Whitehouse, D-R.I., praised Klobuchar and Blumenthal for their efforts to "shine a light on the role of guns in domestic violence.''

"I think we can all agree that we have the same goals here,'' said Malcolm. "We are all concerned with protections (against) domestic violence and more generally public safety. I think the intention is there to do good, and protect women but I think both of these bills have the wrong approach.''

Klobuchar's bill, she said, is far too broad in its definition and would "net large numbers of innocent individuals'' for a misdemeanor crime, such as stalking. She then offered criticism of Blumenthal's bill which would "permit the seizure of firearms from anyone subject to a temporary restraining order.''